PROJECT SUMMARY The goal of this program is the development of a high-resolution, neuroendovascular imaging platform that provides detailed information on intravascular devices used to treat brain aneurysms. Miniaturization of the design features of neurovascular stents and flow-diverters (FD) with braided wires of 20 ?m and laser cut features of 10 ?m, has enabled an explosion of technology available for endovascular treatment of stroke. Despite these advances, however, several questions remain unanswered including the mechanisms of aneurysm rupture after FD treatment, the fate of jailed perforating vessels and long term patency rates. Non-invasive imaging technology has not kept pace with device technology to enable endovascular surgeons sufficient resolution to adequately assess the device-vessel relationship. As such, there is a critical need for high resolution imaging specific to cerebrovascular disease and endovascular treatments. Intra-vascular optical coherence tomography (OCT) is a relatively new imaging technique approved by FDA for the coronary vasculature imaging that delivers the highest axial resolution (~10-15 m) among all other available modalities. However, commercially available OCT catheter sizes (~2.6F ? 1 mm) are not compatible with microcatheters used for neuro-endovascular intervention do not allow for navigation in the highly tortuous neurovascular anatomy. In this application we seek to develop a reduced size, high-resolution imaging catheter compatible with neurovascular microcatheter delivery tools and workflow, capable of navigating tortuous vasculature using novel optics and scanning mechanisms. We aim to demonstrate feasibility in a combination of in vitro vascular phantoms of cerebrovascular pathology and in vivo animals model including cutting edge neuroendovascular implants. Upon completion of this Phase 1 application, we will have sufficient preliminary data showing the superiority of intravascular OCT imaging as compared to gold standard x-ray angiography and cone-beam CT to enter into a commercialization phase that will seek regulatory approval for the technology.